| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide-range power supply circuit capable of attaining stabilization by means of a switching frequency control system using circuitry as simple as possible. SOLUTION: In a switching power supply circuit comprising a resonance type converter, variations in secondary DC output voltage caused by level variation of a commercial AC power supply is stabilized, by performing variable control of switching frequency depending on level variation of the commercial AC power supply. The level of secondary DC output voltage is detected, and a control current Ic is fed to the control winding Nc of an insulation converter transformer PIT employing the structure as a saturable inductor depending on the level error thus performing variable control of the leakage inductance of the insulation converter transformer PIT. Constant voltage control of the secondary DC output voltage can be carried out properly, under such conditions as the load variational width is relatively large in the range from AC 100V system to AC 200V system. COPYRIGHT: (C)2005,JPO&NCIPI
|
